This invention relates to improving the steerability of a snowmobile and more particularly to eliminating the problem of snowmobile ski darting and tracking.
Snowmobile skis typically have elongated steering skags carried on the bottom of the ski that act as a type of keel to increase the bite of the ski in the snow when the ski is turned. Ski skags leave an impression in the snow corresponding to the profile of the ski and skag. Particularly in wet or compacted snow, a snowmobile ski coming upon the impression left by a previous snowmobile ski will tend to follow the same track (especially if the temperature has dropped causing the wet snow to freeze). This effect is known as Tracking or darting. Darting forces the snowmobile operator to compensate or correct for the tracking steering forces by oversteering the vehicle to maintain directional stability. Darting can be quite severe particularly if the snow containing the initial track was wet and has refrozen (such as on a sunny winter day followed by a cold night--typical snowmobiling weather).
The skag of a snowmobile following such a track will naturally situate itself in the previous impression and a considerable effort is required to steer out of such a track. Over time, darting can cause the driver to become fatigued from the effort of steering.
A need exists, therefore, for a snowmobile ski that eliminates the problem of darting. Ideally, such a ski would not only be able to steer easily despite encountering a skag impression but would also leave little skag impression behind it so that later machines that come upon the track will not dart.